Thermostat.



J. D. GULD.

THEBHDSTAT.

Prummel FILED Imm, 190s.

Patented Dec. 19, 1911.

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JOHN D. GOULD, OF NEW YORK, N. Y.

THERMOSTAT.

Specification ot Letters Patent.

Patented Dec. 19, 1911.

Application led February 5, 1909. Serial No. 476,225.

To all whom it may concern.'

Be it known that I, JOHN D. GoULn, a citizen of the United States, and a resident of the city of New York, borough of Brooklyn, in the county of Kings and State of New York, have invented a new and Improved Thermostat, of which the following is a full, clear, and exact description.

This invention is an improvement in thermostats for use in fire-conducting circuits, relating principally to thermostats 0f the character described in Letters Patent granted to Max J. Levy, November 15, 1904, Number 774,847, and wherein is disclosed a thermostatic cable consisting of an inner conductor of low fusing metal, a relatively porous covering thereon, and an exterior enveloping metallic tubular conductor of relatively high fusing point.

The objectof the present invention primarily is to provide a thermostat employing the thermostat-ic cable above mentioned, or a similar cable, and having metal terminals confining the opposite ends of the cable, whereby the same will not be exposed and thereby injured by moisture, and will prevent the escape of the fusible metal when expanded and melted, so that the latter will positively operate to close the current, either at the ends or along the length of the cable.

The invention also has in view asimplified construction adapted to be applied on narrow surfaces, and presenting a neat appearance when installed.

Reference is to be had to the accompanying drawings forming a part of this specification, in which similareharacters of reference indicate corresponding parts in all the views. Y

Figure 1 is a perspective view of a thermostat constructed in accordance with my invention and applied to a ceiling; Fig. 2 is a central longitudinal section of the same; Fig. 3 is a cross-section on the line 3-3 of Fig. 2, looking in the direction of the arrows; Fig. 4 is a perspective view of the thermostatic cable with a small section of its several layers removed to show the construction; and Fig. 5 is a erspective view of a modified form of the tiiermostat.

In the construction of my improved thermostat, I preferably employ a base 5 in the form of a narrow strip of insulating material, which in practice is usually orcelain. This strip has screw openings or attaching it at opposite ends, ordinarily to a ceiling, and is cut out slightly on its under face between its ends, as shown in Figs. l and 2, in order to insure a firm contact at these points. At or near the opposite ends of the base 5, and on its upper face, are arranged binding posts 6, which form the terminals of an open circuit, and are preferably in the form of met-allie blocks which seat in depressions 7 of the base, and are secured therein by screws 8, the latter passing into counter-borings in the rear face of the base.

The binding posts or terminals 6 are provided with the usual binding-screws 9 for attaching the terminals of the circuit, and have sockets in their opposed faces for receiving and confining the opposite ends of a thermostatic cable. The construction of this cable, as best shown in Fig. 4, embodies an inner conductor 10 of metal of relatively high fusing point, copper wire for instance, surrounded by or in contact with a strip of metal 11 of relatively low fusing point; an insulating covering 12 of relatively porous structure and of a material readily dissociated by heat; and a metallic tubular conductor 13, which envelops the whole.

Electric contact of the outer tubular conductor 13 is insured with one of the binding posts 6 by providing the latter with a setscrew 14, threaded through its side, and the opposite end ofthis conductor is insulated from the other binding post by a bushing 15 of hard rubber or other suitable insulating material. It will be noted from Fig. 2, that the binding post which is insulated from the enveloping conductor 13 is constructed with an aperture leading from the inner wall of the socket, through which passes and its the conductor 10, and in which electrical contact of this conductor is insured by a screw 14a threaded through the side of the binding post, as in the case of the screw 14. It will be apparent from this construction that each conductor has electrical contact with one of the binding posts, and is insulated from the other, and in view of the confined ends of the thermostatic cable, the same cannot be injured by moisture and will insure assage of the fusible metal when expandedp and melted, through the insulating covering 12, and thereby close the circuit between the conductors 1() and 13 rather than permit the flow of this metal from the ends of the cable, which in instances might fail to close the circuit.

In Fig. 5 I have shown a modified form of the invention which is in all respects the same as that described, except the cable 13 has an intermediate helical coil 13a. Under a rise of temperature this coil expands and opens the interstices of the Porous insulation 12 and facilitates the completion ot' the circuit and thus adapts the thermostat to operate at a lower temperature than when the cable is straight.

The form of the thermostat makes it oi convenient design to place on surfaces of limited Width, and will, when installed, be as serviceable as more complicated and expensive constructions.

Having thus described my invention, I claim as new and desire to secure by Letters Patent.:

l. In a thermostat, an insulating base having binding posts provided With sockets, a therinostatie cable having the opposite ends thereof passing into said sockets and composed of an inner and outer conductor provided with an intervening metal of low fusing and a porous insulation, the opposite ends oi the cable arranged within the sockets, with one colnluctor insulated from lach binding post` and in Contact with the other binding post, and means for binding each of the conductors in the binding posts with which they contact and thereby insuring electrical contact therebetween.

2. 111 a thermostat, terminals, a thermostatic cable con'iprising an inner and outer cont'luctor having a porous insulation and a. metal of low t'using between them, the metal adapted when melted to penetrate the insulation and electrically connect the conductors, the thermostatic cable having an inter! mediate coil to Jfacilitate the Working of 'the tlierniostat, with the ends of the cable extending in opposite directions and confined vvithin the terminals.

In testimony whereof I have signed my naine to this specification in the presence of tvvo subscribing Witnesses.

JOHN D. GOULD.

Witnesses IV. W. Hom', JOHN P. DAvis.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

